Cleaning of Bio-filter

[Angie]

I'm very confused at this moment about whether or not my bio-filter will need to be cleaned. If so, which parts do I clean? I don't want to mess up my beneficial bacteria....

 

[JohnHuff]

What kind of biofilter do you have?

 

[Angie]

I have a 35 gal. barrel with sponges in net bags.

 

[JohnHuff]

Is it a Skippy type? Assuming that you have one, take the net bags out and flush the rest of the barrel. The sponges should contain the beneficial bacteria. What's at the bottom of the barrel should be gunk. Don't use chlorinated tap water but pond water or some other safe water.

Also, how long have you been running it and has it ever been cleaned?

 

[j.w]

And when you take the net bags out just dunk them in a big tub of your pond water to clean off the gunk.......swish around till most of the big gunk is gone.

 

[don't ask]

Angie, good suggestions from the members and i was gonna add that people do it at different intervals...some people may clean when they notice that the flow has dropped considerably.. others at the end of season, beginning of season(if you ran pump through the winter) and maybe once or twice during the summer..not gonna say right or wrong to when just that you don't do it too often..

 

[Waterbug]

There is a difference between mechanical and bio filters.

A mechanical filter traps bits of crap and is cleaned from time to time to remove the crap from the pond. Slowing water flow is the classic sign it's time to clean. In this very low oxygen environment only anaerobic bacteria can live.

A bio filter provides a home to bacteria which convert toxic ammonia and nitrite into safer matter. The species of bacteria grown in a bio filter are called Nitrosomonas and Nitrobacter. They need oxygen to carry out their function.

Can you see the problem? If you have submerged sponges covered in gunk you have virtually no beneficial bacteria in the sponges. The beneficial bacteria in your pond are only on liner, pipes and hoses, etc., any surface clean from gunk so they can get O2.

I have read in water gardening forums and web sites so many times..."don't clean your filter with chlorinated water because it will kill beneficial bacteria". There are just thousands of web sites and millions of people repeating this classic myth. It's not just a lack of understanding the bacteria envolved, but a lack of even caring whether information is correct or not. It's not like it's complicated. Just sad there is zero hope of it ever being corrected.

The most common bacteria found in gunk covered sponges would be Aeromonas hydrophila. Same bacteria people with expensive Koi fear the most because it's one of the flesh eating bacteria. Same one responsible for the recent college kid loosing her limbs and a chunk of her torso. I have to ask...why in the world would anyone want to "save" this bacteria?

Wash the sponges any way you like, chlorinated water is fine. If media media needs to be cleaned it is not a bio filter, can't be bio filter any more than you can breath water. People can call it a bio filter, they can call it a moose dancing in a tutu...it ain't.

 

[JohnHuff]

The most common bacteria found in gunk covered sponges would be Aeromonas hydrophila.

I'm going to have to disagree with you here unless you can provide some references.

WB, after I read that Norm Meck article, I had been wondering if the the low flow gunk covered media in Skippys was harboring the heterotrophic bacteria that Norm Meck alluded to. And due to the low flow and similar conditions it's possible that the same thing is happening in the gunk covered media of the Skippy that is happening in the schmutzdecke of the biosand filter. You can read about schmutzdecke here: http://www.biosandfi.../229#Principles
I've actually built a small test bed to test that and in 4-6 weeks (weather permitting), I'll be taking some water to test for bacteria.

 

[Waterbug]

I'm going to have to disagree with you here unless you can provide some references.

Good catch. I should have typed "A" instead of "The most", should be:

A common bacteria found in gunk covered sponges would be Aeromonas hydrophila.

I would assume Skippy and the Biosand filter in the link act about the same bacteria wise. Although the article calls the filter a biosand filter I would not consider it a bio filter when used in a pond. Nitrifying bacteria are everywhere. If the criteria for calling something a bio filter is it must have at least one nitrifying bacterium then my hand is a bio filter when I dip it into the pond.

S/G (sand & gravel) filters being used in Koi ponds today do contain some nitrifying bacteria but I've never read of anyone using one as bio filter. People go out of their way to say they shouldn't be used as the primary bio filter. They're used in the same way the "biosand" filter in the article is used, to remove small particles. When knowledgeable pond keepers say "bio filter" they're referring to a filter that converts a substantial amount of ammonia and nitrite. They understand that ammonia/nitrite conversion is happening everywhere, but they generally don't refer to everything as a bio filter.

As the article says, there's only a thin layer of bacteria getting enough O2 to survive. So if the filter was huge, like the size of a pond, I could see that being called a bio filter as it would be able to convert a lot of ammonia/nitrite. And the point about a thin layer of water would be important. But now we're back to what makes a TT and Shower so good at conversion, a thin sheet of water over the media.

I'll be interested to read about the result of your test.

 

[JohnHuff]

WG, the biosand filter I linked to is not a biofilter in the sense that we ponders use the word. They use it for purifying drinking water in the 3rd world and the flow rate is much too low for ponds. Some cities in the US are using huge ones to clean their drinking water.

I mainly like small and easy to build filters so when I saw how much sand was needed for S/G filters I knew that it wasn't for me. Besides, I felt that the backflushing is sure to displace the layers of sand and gravel, no matter what their owners say. Do you have a link to any good ones that's not the Birdman link?

The weather here is not co-operating on my test filters. I think it needs at least 70F for the bacteria to grow and we haven't had that 5 days in a row.

 

[Waterbug]

WG, the biosand filter I linked to is not a biofilter in the sense that we ponders use the word. They use it for purifying drinking water in the 3rd world and the flow rate is much too low for ponds. Some cities in the US are using huge ones to clean their drinking water.

That's my understanding too. In San Jose we had huge percolation ponds doing this to recharge the aquifers we drew water from.

I mainly like small and easy to build filters so when I saw how much sand was needed for S/G filters I knew that it wasn't for me. Besides, I felt that the backflushing is sure to displace the layers of sand and gravel, no matter what their owners say. Do you have a link to any good ones that's not the Birdman link?

I have no link...I agree 100%. They don't make sense to me at all. But I've never used one. Closest I've come is a huge percolation sand filter, about 1/2 ton of sand, failed in a couple of minutes. My first filter I think. Was sure it was going to work.

 

[crsublette]

Heh, seems like a good example of a S/G filter would be a bog. I know technically ya don't put sand in the bog (figure a fella could tho and different size rocks), but overtime fine "sand" type material will be introduced with dirt blowing and other stuff being pushed into a bog. Also, I read about how bogs are "purged" somehow, but I also hardly read about anyone actually doing this.

WG, the biosand filter I linked to is not a biofilter in the sense that we ponders use the word. They use it for purifying drinking water in the 3rd world and the flow rate is much too low for ponds. Some cities in the US are using huge ones to clean their drinking water.

That's my understanding too. In San Jose we had huge percolation ponds doing this to recharge the aquifers we drew water from.

Yeah, I think the extremely slow flow rate and the very fine medium is what cleans the water so well. Almost sounds like it works like a Reverse Osmosis filter system except it is just much bigger and more economical.